Holocene Climate Evolution And Glacier Fluctuations Inferred From Proglacial Lake Sediments At Hvítárvatn, Central Iceland, 2013 University of Colorado Boulder
Holocene Climate Evolution And Glacier Fluctuations Inferred From Proglacial Lake Sediments At Hvítárvatn, Central Iceland, Darren Jon Larsen
Geological Sciences Graduate Theses & Dissertations
Understanding the character and expression of past climate changes in response to discrete forcing mechanisms is prerequisite to a critical assessment of modern climate variability and to anticipating future changes to Earth’s climate system. In this dissertation, Holocene paleoclimate and glacier fluctuations in central Iceland are reconstructed using the sediment archive preserved in proglacial lake Hvítárvatn. Sediment cores retrieved from >35 locations throughout Hvítárvatn’s main basin are used in conjunction with seismic reflection profiles and multibeam bathymetric data to construct a detailed record of environmental conditions and the changing dimensions of the adjacent Langjökull ice cap (925 km ...
Viscoelastic Response To Surface And Tidal Loading – Applications To Glacial Isostatic Adjustment Of The Earth And Tidal Deformation Of The Icy Satellites, 2013 University of Colorado at Boulder
Viscoelastic Response To Surface And Tidal Loading – Applications To Glacial Isostatic Adjustment Of The Earth And Tidal Deformation Of The Icy Satellites, Geruo A
Physics Graduate Theses & Dissertations
Observations of glacial isostatic adjustment (GIA), the viscoelastic relaxation of the Earth induced by deglaciation following the last glacial maximum, have provided valuable constraints on late Pleistocene ice history and on the internal viscoelastic structure of the solid Earth. The GIA signal is also a significant source of noise for other applications. For example, errors in GIA models due to errors in the assumed ice deglaciation history and mantle viscosity structure, are generally assumed to be the largest source of uncertainty when using GRACE time-variable satellite gravity data to estimate present-day thinning rates of the Antarctic ice sheet.
The same ...
Basal Crevasses And Suture Zones In The Larsen C Ice Shelf, Antarctica: Implications For Ice Shelf Stability In A Warming Climate, 2013 University of Colorado at Boulder
Basal Crevasses And Suture Zones In The Larsen C Ice Shelf, Antarctica: Implications For Ice Shelf Stability In A Warming Climate, Daniel J. Mcgrath
Geography Graduate Theses & Dissertations
Understanding ice shelf structure and processes is paramount to future predictions of sea level rise, as nearly 75% of the ice flux from the Antarctic Ice Sheet (AIS) passes through these gates. The breakup of an ice shelf removes the longitudinal back stress acting on the grounded inland ice and leads to flow acceleration, dynamic thinning and frontal retreat, processes that can be sustained for more than a decade. Increased ice discharge to the ocean contributes to global sea level rise. This dissertation investigates basal crevasses and suture zones, two key structural components of ice shelves, in order to understand ...
Do Cryoconite Holes Have The Potential To Be Significant Sources Of C, N, And P To Downstream Depauperate Ecosystems Of Taylor Valley, Antarctica?, Elizabeth A. Bagshaw, Martyn Tranter, Andrew G. Fountain, Kathleen A. Welch, Hassan J. Basagic, W. Berry Lyons
Geology Faculty Publications and Presentations
Nutrient recycling occurs in hydrologically isolated cryoconite holes on the glaciers of the McMurdo Dry Valleys, Antarctica. Biogeochemical processes enrich the cryoconite holes with solute and nutrients compared to the source sediment and glacier ice. The position of the glacier within the landscape affects the physical and biogeochemical character of the cryoconite holes, with those found in more biologically productive areas of the valley having higher concentrations of C, N, and P and higher pH. Comprehensive assessment of the quality and quantity of bioavailable C, N, and P shows that the cryoconite holes represent a significant store of nutrient in ...
7700 Years Of Holocene Climatic Variability In Sermilik Valley, Southeast Greenland Inferred From Lake Sediments, 2013 University of Massachusetts Amherst
7700 Years Of Holocene Climatic Variability In Sermilik Valley, Southeast Greenland Inferred From Lake Sediments, Samuel H. Davin
Masters Theses 1911 - February 2014
During the latter half of the 20th century until present day there has been an unprecedented rise in global annual mean temperatures accompanied by rising sea levels and a decrease in Northern Hemisphere snow cover, which if it continues will lead to widespread disruption of climate patterns, ecosystems, and present-day landscapes. It is therefore of critical importance to establish an expanded network of paleoclimate records across the globe in order to better assesses how the global climate system has changed in the past, that we may create a metric by which to address modern change. Herein is presented a7 ...
Collaborative Research: High-Resolution Studies Of Glacier Dynamics At Two Major Outlet Glaciers In East Greenland, 2012 Principal Investigator; University of Maine, Orono
Collaborative Research: High-Resolution Studies Of Glacier Dynamics At Two Major Outlet Glaciers In East Greenland, Gordon S. Hamilton
University of Maine Office of Research and Sponsored Programs: Grant Reports
The Principal Investigators request support for an interdisciplinary, high-resolution study involving remote sensing and field investigations at two of Greenland's largest outlet glaciers. The study of the Helheim and Kangerdlugssuaq Glaciers will integrate seismological, glaciological, and geodetic observations to build an understanding of flow dynamics at major outlet glaciers, which represent a critical junction between the atmosphere, cryosphere, and hydrosphere. The project would be the first long-term occupation of an outlet glacier by a GPS receiver network, and would address questions of flow variation on earthquake to interannual time scales. Recent discoveries have made it clear that our understanding ...
Geogram 2012, 2012 Western Kentucky University
Geogram 2012, David J. Keeling, Wku Department Of Geography And Geology
Geography and Geology Publications
No abstract provided.
Investigating The Holocene History Of Eliot Glacier, Mount Hood, Oregon, 2012 Portland State University
Investigating The Holocene History Of Eliot Glacier, Mount Hood, Oregon, Nadia Sittara Jones
Dissertations and Theses
This research documents the Holocene glacial history of Mount Hood, Cascade Mountains, Oregon by analyzing a set of three lateral moraines abutting Eliot Glacier, the largest glacier on the mountain. This study seeks to: 1) establish the relative ages of these lateral moraines and 2) determine if these features represent distinct glacial advances. The hypothesis is that the lateral moraines for Eliot Glacier represent three distinct periods of glacial advance based on their position relative to the current glacier and other diagnostic indicators. Soil profiles of three positions (shoulder, backslope, and footslope) on the distal side of each lateral moraine ...
Climate Change Resource Directory, 2012 University of Southern Maine
Climate Change Resource Directory, New England Environmental Finance Center
Sustainable Communities Capacity Building
The impacts of a changing climate – from sea level rise to altered weather patterns – will affect local governments’ efforts to manage stormwater, treat wastewater, and provide clean drinking water in their communities. This resource list was compiled to help local governments plan and implement climate change adaptation strategies. It was developed by the Environmental Finance Center Network through the Capacity Building for Sustainable Communities program funded by the U.S. Department of Housing and Urban Development and the Environmental Protection Agency. Through this program, EFCN is providing capacity building and technical assistance to recipients of grants from the federal Partnership ...
Ice Dynamics And Surface Glaciology Along Us Itase Traverse Routes In East Antarctica, 2012 Principal Investigator; University of Maine, Orono
Ice Dynamics And Surface Glaciology Along Us Itase Traverse Routes In East Antarctica, Gordon Hamilton
University of Maine Office of Research and Sponsored Programs: Grant Reports
This award supports a series of field measurements that will improve our understanding of the East Antarctic ice sheet. The objectives of this project are to take advantage of the overland traverse logistics framework provided by US ITASE and to collaborate with other US ITASE investigators to calculate rates of ice sheet thickness change (mass balance) on domes, along elevation contours and along flow lines in East Antarctica using precise global positioning system methods. In addition, the variability (both spatial and temporal) in snow accumulation rates will be assessed using shallow ice cores and ground-penetrating radar profiling, and will provide ...
Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, 2012 University of Nebraska-Lincoln
Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui
Papers in the Earth and Atmospheric Sciences
This paper provides documentation of unexpectedly high-reservoir-quality glaciomarine sands found in the Cenozoic succession beneath McMurdo Sound, Antarctica, as an analogue study for evaluations of hydrocarbon prospectivity in basins elsewhere. The Oligocene to Lower Miocene succession of the Victoria Land Basin, an extant portion of the West Antarctic Rift System, comprises diamictites, mudrocks, and sandstones with minor conglomerates. These lithologies are arranged in repetitive stacking patterns (cycles), interpreted to record repeated advance and retreat of glaciers into and out of the basin, with attendant eustatic and isostatic effects. Phases of ice retreat within the cycles comprise an array of mudrocks ...
Shoreline Analysis And Barrier Island Dynamics: Decadal Scale Patterns From Cedar Island, Virginia, 2012 University of Delaware
Shoreline Analysis And Barrier Island Dynamics: Decadal Scale Patterns From Cedar Island, Virginia, Stephanie Nebel, Art Trembanis, Donald Barber
Donald C Barber
Aerial photography, topographic maps, high-resolution satellite imagery, and global positioning system (GPS) data were compiled in ArcMAPTM and analyzed using the Digital Shoreline Analysis System (DSAS) to determine decadal trends of shoreline movement on Cedar Island, Virginia. Shoreline retreat rates for Cedar Island had an alongshore average of 24.1 m/y based on simple endpoint analysis (1852–2007), while the short-term (1994–2007) retreat rates increased to 212.6 m/y. Retreat statistics were further calculated for the time intervals 1852–1910 (25.1 m/y), 1910–62 (23.5 m/y), 1962–80 (23.9 m/y), 1980 ...
Subglacial Clast/Bed Contact Forces, 2012 Iowa State University
Subglacial Clast/Bed Contact Forces, John Byers, Denis Cohen, Neal R. Iverson
Geological and Atmospheric Sciences Publications
A laboratory device was built to measure the forces that ice exerts on a 0.05 m diameter rigid plastic sphere in two different configurations: in contact with a flat bed or isolated from the bed. Measurements indicated that bed-normal contact forces were 1.8 times larger than drag forces due to creeping flow past a slippery sphere isolated from the bed. Measurements of forces as a function of the bed-normal ice velocity, estimations of the ice viscosity parameter and observations of markers in the ice indicate ice is Newtonian with a viscosity of ∼1.3 × 1011 Pa s. Newtonian ...
Evolution With Depth From Detrital To Authigenic Smectites In Sediments From And-2a Drill Core (Mcmurdo Sound, Antarctica), 2012 Università degli Studi di Siena
Evolution With Depth From Detrital To Authigenic Smectites In Sediments From And-2a Drill Core (Mcmurdo Sound, Antarctica), Francesco Iacoviello, Giovanna Giorgetti, Fernando Nieto, Isabella Turbanti Memmi
ANDRILL Research and Publications
We have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the drill core it was possible to split the sequence into three units. Smectites throughout the core are either detrital or authigenic. Detrital smectites are close to montmorillonite-beidellite in composition while newly-formed smectites frequently have higher Fe-Mg contents and intermediate compositions between the saponite and nontronite ...
Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, 2012 University of Dayton
Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya
Geology Faculty Publications
Meltwater runoff modeling from glacierized basins needs several input data, including total meltwater contributing area. This study utilizes optical remote sensing data to assess glacierized basins in the central Himalayas where snow and glaciers contribute substantially to the water resources. Result shows that there are four main water-bearing zones in the basin: (a) dry snow, (b) wet snow, (c) exposed glacial ice, and (d) debris-covered glacial ice, and it is possible to differentiate and map these zones and their spatio-temporal variations from satellite sensor data. These zones can then be incorporated in meltwater runoff modeling as separate entities because they ...
Instruments And Methods: A Method For Recording Ice Ablation Using A Low-Cost Ultrasonic Rangefinder, 2012 University of Minnesota, Morris
Instruments And Methods: A Method For Recording Ice Ablation Using A Low-Cost Ultrasonic Rangefinder, M. Len Keeler, Keith A. Brugger
We have adapted inexpensive ultrasonic rangefinders to measure ablation rates on the surface of a glacier.While ultrasonic rangers are commercially available for this purpose, our goal was to utilize rangefinders typically used in hobby robotics without significantly compromising performance. To correct for environmental factors that affect the speed of sound we use two ultrasonic rangefinders, one focused on a fixed target. Measurements of ablation correlate well with manual measurements with an uncertainty of about 3 cm, suggesting an accuracy comparable with other non-manual methods of recording ablation. The limitations of our rangefinder include those inherent in commercially available units ...
Late Pleistocene And Holocene Aged Glacial And Climatic Reconstructions In The Goat Rocks Wilderness, Washington, United States, 2012 Portland State University
Late Pleistocene And Holocene Aged Glacial And Climatic Reconstructions In The Goat Rocks Wilderness, Washington, United States, Joshua Andrews Heard
Dissertations and Theses
Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium ...
Climb To The Ice, 2012 Indiana University Maurer School of Law
Climb To The Ice, Richard Vaughan
Articles by Maurer Faculty
The article, originally presented as a lecture, discusses George Bird Grinnell's 1887 climb of the Montana glacier that eventually become known as Grinnell Glacier. Grinnell’s efforts to establish Glacier National Park are detailed. Grinnell's previously unpublished descriptions of the glacier and its surrounding area are analyzed by the author.
Originally delivered as a lecture at the Montana History Conference, October 2, 2010. Full issue available at: http://issuu.com/um_crown_gye/docs/crownofthecontinent-autumn2012
Glacier-Bed Geomorphic Processes And Hydrologic Conditions Relevant To Nuclear Waste Disposal, 2011 Iowa State University
Glacier-Bed Geomorphic Processes And Hydrologic Conditions Relevant To Nuclear Waste Disposal, Neal R. Iverson, Mark Person
Geological and Atmospheric Sciences Publications
Characterizing glaciotectonic deformation, glacial erosion and sedimentation, and basal hydrologic conditions of ice sheets is vital for selecting sites for nuclear waste repositories at high latitudes. Glaciotectonic deformation is enhanced by excess pore pressures that commonly persist near ice sheet margins. Depths of such deformation can extend locally to a few tens of meters, with depths up to approximately 300 m in exceptional cases. Rates of glacial erosion are highly variable (0.05–15 mm a−1), but ratesa−1 are expected in tectonically quiescent regions. Total erosion probably not exceeding several tens of meters is expected during a glacial ...
High-Resolution Study Of Layering Within The Percolation And Soaked Facies Of The Greenland Ice Sheet, 2011 University of Montana - Missoula
High-Resolution Study Of Layering Within The Percolation And Soaked Facies Of The Greenland Ice Sheet, Joel Brown, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, John H. Bradford
Geosciences Faculty Publications
Within the percolation and soaked facies of the Greenland ice sheet, the relationship between radar-derived internal reflection horizons and the layered structure of the firm column is unclear. We conducted two small-scale ground-penetrating radar (GPR) surveys in conjunction with 10 m firm cores that we colleced within the percolation and soaked facies of the Greenland ice sheet. The two surveys were separated by the distance of about 50 km and about 340 m of elevation leading to about 40 days of difference in the duration of average annual melt. At the higher site (about 1997 ma.s.l.), which receives ...